The present invention generally relates to workpiece positioning systems, and more particularly to a modular apparatus and system for positioning a workpiece.
Workpiece positioning an systems are well known in the art. For example, U.S. Pat. No. 4,655,445, issued to Morse discloses an apparatus for selectively positioning a workpiece adjacent to a guide on a substantially planar work surface of a power tool assembly. The positioning apparatus is adapted to selectively position the workpiece at selected ones of a plurality of predetermined lateral offsets with respect to a cutter. The positioning apparatus includes an indexing member having a plurality of index holes and an elongated index pin element. The indexing member is affixed to either the workpiece or the guide, and the pin element is affixed to the other of the workpiece or the guide, so that the workpiece may be positioned adjacent to the indexing member and the guide, with the pin element extending through and interferingly engaging one of the index holes. This apparently permits the generation of a succession of cuts in a workpiece which are substantially uniformly spaced along a reference axis.
U.S. Pat. Nos. 4,500,079 and 4,801,225, issued to Morghen disclose a removable and replaceable locating pin adapted to locate a workpiece on a tooling fixture for machining. The locating pin is adapted to cooperate with a workpiece for positioning the workpiece in various directions of restraint. The locating pin is provided with manually actuatable locking means that permit easy adjustment or removal of the specific locator pin as a particular machining operation may require.
U.S. Pat. No. 4,896,086, issued to Miyahara, et al., discloses a method and apparatus for positioning a workpiece to a pallet on a working line. The line transports plural kinds of workpieces. Plural positioning pins are provided at various locations on each pallet to enable all the workpieces to be carried by the pallets. Each positioning pin has a set position and a reset position. All positioning pins are first reset to the reset position, thereafter, a selected positioning pin is set to the set position to accommodate a particular kind of workpiece. The positioning of the workpiece is accomplished by fitting a positioning hole defined by the selected workpiece onto the selected positioning pin.
U.S. Pat. No. 4,968,012, issued to Haddad, et al., discloses a modular workpiece holding apparatus for locating and holding a workpiece in a predetermined position. The apparatus includes a base having a plurality of external faces, each with a plurality of bores arranged in an X-Y grid pattern of parallel rows. The bores alternate vertically and horizontally between first and second different diameter bores. A riser is mounted at a predetermined position on the base by bushings and fasteners extending between the riser and the bores in the base. The bushings in each riser are arranged in diagonally opposed pairs such that one pair of bushings engages the first diameter bores in the base, while the second opposed pair of bushings engages the second enlarged diameter bores in the base. A workpiece attachment member is mounted on the mounting head end of each riser to locate and hold a workpiece. The mounting head of each riser is axially in line with the riser mounting base or offset from the riser mounting base. Each bushing includes an internal bore having a threaded end portion and an enlarged, coaxial, smooth portion. Each fastener includes a plurality of threads adjacent one end and an unthreaded portion extending from the threaded end so as to be movably retainable within a bushing in the riser mounting base after the threaded end portion of the fastener is threaded through the threaded end of the bore in the riser mounting base.
U.S. Pat. No. 5,026,033, issued to Roxy, discloses a universal system for support and positioning a workpiece for use with a device such as an inspection system. A plurality of individual alignment devices are inserted into predetermined holes of a platform having a matrix of holes. Individual alignment devices support, clamp, datum point position, and provide reference points. Each alignment device includes stanchions of varying length. These stanchions appear to be capable of being connected to each other. Once an alignment device is positioned in a hole, it can be fine tuned in all directions to get an exact location, so that workpieces of widely varying types, shapes and sizes can be positioned using the same set of alignment devices.
U.S. Pat. No. 5,044,616, issued to Jakob discloses a locating device for positioning a workpiece on a processing apparatus. A first embodiment includes a base and a fixture plate with positioning means between the base and the fixture plate. An abutment defines a fixed reference point for locking the fixture plate on the base through a clamping mechanism. The clamping mechanism also includes release cylinders so that the fixture plate can be quickly interchanged for introducing a new workpiece. A second embodiment includes a base structure that comprises a first clamping unit and a second clamping unit that support a fixture plate. First positioning means secured to each clamping unit cooperate with second positioning means secured to the fixture plate. Clamping means engage and lock the fixture plate in position. The clamping means include locking members that are slidably disposed in channels in the blocks.
U.S. Pat. No. 5,362,036, issued to Whiteman discloses a modular welding fixture for positioning a workpiece. The fixture includes a base table having an array of openings through the surface and an array of locator mounting holes co-located in spaced relationship, with respect to the openings, to accommodate at least one vertical end locator having a base plate that is removably mountable to the base table at preselected positions. The locator has means for locating and holding at least a portion of a workpiece. The fixture further includes at least one horizontal locator having a base plate that is removably mountable to the base table at preselected positions, and the base plate includes means for locating and holding at least a portion of a workpiece.
U.S. Pat. No. 5,481,811, issued to Smith discloses a modular system for the support and positioning of a workpiece for use with an inspection system. The modular system includes a base having a plurality of exterior faces, at least some of which have an array of equally spaced holes forming a grid pattern. At least one riser is attached to the base cube by a fastener, which can be inserted into the riser by defeating an outwardly biased locking member at the inner end of the fastener, extending through the riser and into the holes of the base cube. The fastener is used to provide positive location and fastening of the risers to the base cube. Functions of individual risers include support, clamping, datum point positioning and providing reference points.
U.S. Pat. No. 5,516,089, issued to Seniff et al., discloses a workpiece locating unit that is receivable in a T-slot formed in a workpiece supporting table member. It provides a pin or other locating device cooperable with a locating feature on a workpiece to aid in accurately positioning the workpiece on the work supporting surface of the table member. The unit has four corners each providing an abutment surface for engagement with one or the other of two vertical slot surfaces. Two diagonally opposite ones of the abutment surfaces are rigid and the other two diagonally opposite ones of the abutment surfaces are resilient. The resilient abutment surfaces resiliently engage the two vertical surfaces of the slot and urge the unit about a vertical axis to hold the rigid abutment surfaces engaged with the vertical slot surfaces eliminating lateral looseness between the unit and the table member and providing accurate positioning of the locating device of the unit as the unit is moved from one position to another along the length of the slot.
These and other prior art positioning systems often require well trained and technically sophisticated personnel to properly operate them. This adds to the cost and complexity of such systems. Also such prior art positioning systems do not lend themselves to a modular design that allows for fine adjustments of position of a workpiece through the selection of easily identifiable and assembled modular parts. As a consequence, there has been a long felt need for a workpiece positioning system that avoids the foregoing problems in the prior art.
The present invention provides a fixture for locating a workpiece in space comprising a blade having a longitudinal axis, a bottom edge, a top edge, and a plurality of through-bores. At least two of the through-bores are positioned on the blade so as to define a predetermined location relative to the top and bottom edges, and together with a riser, allow for the precise positioning of a locating pin, or other datum point locator, that may be attached to the blade. The blade also includes a mounting arm that is eccentrically located on a top edge. The mounting arm has a plurality of through-bores wherein at least two of the through-bores comprise a predetermined location relative to the top edge. A locating pin, or other datum point locator is attached to the mounting arm.
The present invention is particularly adapted for use in a modular system of fixtures, in that by stocking a variety of blades, each with a different set of through-bore locations, a different positioning fixture may be formed, as needed, without the need for custom manufacturing of blades. Also, due to the eccentric location of the mounting arm on the blade, a simple rotation of the blade about its longitudinal axis allows for a doubling of the locations at which a locating pin, or other datum point locator may be positioned in space.
In one embodiment of the invention, a kit for forming a variety of fixtures for positioning a workpiece is provided that includes a plurality of position determining modules wherein each module comprises a blade having a longitudinal axis, a bottom edge, a top edge, and a plurality of position determining modules wherein each module comprises a blade having a longitudinal axis, a bottom edge, a top edge, and a plurality of through-bores. At least two of the through-bores positionally correspond to at least two through-bores in the top portion of the riser. In this way, when the through-bores of the blade are positioned in aligned relation with the through-bores of the riser, the top edge of the blade is at a predetermined, and known position. The blade further includes a mounting arm eccentrically located on the top edge, relative to the longitudinal axis. The mounting arm has a plurality of through-bores wherein at least two of the through-bores comprise a predetermined location relative to the top edge of the blade. Thus, a kit of blades formed in accordance with the invention may be stocked so that a variety of positioning fixtures may be formed, as needed, without the need for custom manufacturing blades.